NON-UNIFORM ARTIFICIAL TURF INFILL

Abstract

An artificial turf simulating grass including a layer of dispersed non-uniform, polyvinyl chloride-based particulates having non-symmetrical shapes and different sizes.

Claims

1. An artificial turf comprising synthetic filaments or fibers simulating grass adhered to a backing and an infill having a layer dispersed as a layer of non-uniform, polyvinyl chloride-based particulates between the filaments or fibers, wherein the particulates include non-symmetrical shapes and different sizes.

2. The artificial turf of claim 1, wherein the particulates are at least one of pellets and granules.

3. The artificial turf of claim 2, wherein the particulates include at least three different sizes.

4. The artificial turf of claim 3, wherein at least some of the particulates include an elliptic shape.

5. The artificial turf of any claim 3, wherein at least some of the particulates include an ovate shape.

6. The artificial turf of claim 3, wherein at least some of the particulates include an obovate shape.

7. The artificial turf of claim 3, wherein at least some of the particulates include a biconvex shape.

8. The artificial turf of claim 3, wherein at least some of the particulates include an asymmetrically oval shape.

9. The artificial turf of claim 3, wherein at least some of the particulates include a lachrymiform shape.

10. The artificial turf of claim 3, wherein the particulates include a plurality of different shapes selected from the group consisting of an elliptic shape, ovate shape, obovate shape, biconvex shape, asymmetrically oval shape, and lachrymiform shape.

11. The artificial turf of claim 2, wherein at least some of the particulates include an elliptic shape.

12. The artificial turf of claim 2, wherein at least some of the particulates include an ovate shape.

13. The artificial turf of claim 2, wherein at least some of the particulates include an obovate shape.

14. The artificial turf of claim 2, wherein at least some of the particulates include a biconvex shape.

15. The artificial turf of claim 2, wherein at least some of the particulates include an asymmetrically oval shape.

16. The artificial turf of claim 2, wherein at least some of the particulates include a lachrymiform shape.

17. The artificial turf of claim 2, wherein the particulates include a plurality of different shapes selected from the group consisting of an elliptic shape, ovate shape, obovate shape, biconvex shape, asymmetrically oval shape, and lachrymiform shape.

18. The artificial turf of claim 1, wherein the particulates include a plurality of different shapes selected from the group consisting of an elliptic shape, ovate shape, obovate shape, biconvex shape, asymmetrically oval shape, and lachrymiform shape.

19. The artificial turf of claims 18, further comprising a layer including sand underlying the layer of polyvinyl chloride-based particulates.

20. The artificial turf of claim 1, further comprising a layer including sand underlying the layer of polyvinyl chloride-based particulates.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1 is a photograph of PVC infill pellets having different irregular shapes and different sizes in an embodiment of the invention.

[0008] FIG. 2 is a front view of a multi-hole extrusion die having different size holes for producing PVC infill pellets as shown in FIG. 1 in an embodiment of the present invention.

[0009] FIG. 3 is a front partial and magnified view of a multi-hole extrusion die of FIG. 2 in an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0010] As shown in one embodiment in FIG. 1, PVC-based particulates 5 for artificial turf infill include a variety of non-uniform shapes and sizes. Generally, the particulates are irregular, such as non-symmetrical shapes that resemble seeds and/or liquid droplets. PVC-based particulates 5 preferable for use in embodiments of the invention include such PVC granules and pellets having compositions as described in the '956 Publication, which is incorporated herein by reference. Further, the PVC-based particulates 5 may be manufactured in accordance with conventional extrusion, pelletizing and molding methods. In embodiments of the invention, PVC granules and pellets may be manufactured in accordance with methods described and/or referenced in the '956 Publication.

[0011] In one embodiment, an extrusion die 20 as shown in FIGS. 2 and 3 may be used to produce PVC particulates 5 having multiple shapes and sizes in accordance with the invention. It will be appreciated by those skilled in the relevant art of extruding, pelletizing and molding of PVC compositions that the manufacturing parameters, such as run rate, temperature settings, and the like, for optimally producing PVC pellets, granules and particulates as in the present invention will depend on a number of factors such as particular machine being used, the particular environment for manufacturing, the precise composition of PVC-based material, and similar variables. Arriving at desirable results as part of the manufacturing process for PVC-based infill shaped and sized in accordance with the invention will therefore be well within the scope of a person skilled in the relevant art and are not considered critical to the present invention.

[0012] In one embodiment shown in FIGS. 2 and 3, the extrusion die 20 includes numerous rings of different sized holes, such as a ring of first holes 30, a ring of second holes 32, a ring of third holes 34 and a ring of fourth holes 36. The holes are of different sizes so that a variety of non-uniform irregularly shaped and various-sized PVC particulates 5 may be produced. It will be appreciated that configurations for holes, number of holes, shapes of holes, distance between holes and alignment of holes (whether rings, grids or other patterns) may be varied from the depicted embodiment while still supporting the production of irregular, non-uniform and various-sized PVC particulates 5 in other embodiments of the invention.

[0013] In embodiments of the invention, the use of irregular, non-uniform and various-sized PVC particulates 5 imparts improved performance characteristics to artificial turf as compared to uniform particulates disclosed in the '956 application. In the Tables I-III test results subsequently described, uniform PVC-based infill particulates used in artificial turf according to the '956 application are referenced as 20s/50TPE_PriorArt, non-uniform PVC infill particulates that have not been subjected to wear simulation used in artificial turf according to an embodiment of the present invention are referenced as 70/30 Pre-Wear, and non-uniform PVC infill particulates used in artificial turf that have been subjected wear simulation machine with a Lisport-brand wear machine are referenced as 70/30 Post-Wear.

[0014] To compare performance characteristics, each 20s/50TPE_PriorArt, 70/30 Pre-Wear and 70/30 Post-Wear particulates were provided in artificial turf and subjected to the following described tests. The 20s/50TPE_PriorArt particulates were provided in an artificial turf test system of 20 lbs sand/50 lbs thermoplastic elastomer (TPE) over 2 Turf. The 70/30 Pre-Wear particulates were provided in an artificial turf test system of 4.97 lbs per sq. ft. PVC, 2.13 lbs per sq. ft. Sand, 2.25 slit film turf and no pad. The 70/30 Post-Wear particulates were provided in an artificial turf test system of 4.97 lbs per sq. ft. PVC, 2.13 lbs per sq. ft. Sand, 2.25 slit film turf and no pad and subjected to 20,000 cycles of a Lisport wear machine.

[0015] The following laboratory tests were conducted on each of the particulates/artificial turf system samples. Technical guidelines of the Synthetic Turf Council (STC) are incorporated herein by reference. EN references are to European Standards which are also incorporated herein by reference.

[0016] Force Reduction (%)(STC Advanced Artificial Athlete Protocol test) Measures the impact absorption provided by a surface to a player under foot as they run. A lower value describes a surface that is harder underfoot. The results are compared to the STC performance guidelines of 57% to 68% for a Community Field and 62% to 68% for a Stadium Field.

[0017] Vertical Deformation (mm)(STC Advanced Artificial Athlete Protocol test) Measures the amount a surface compresses as an athlete runs across it. This value is often related to speed of play and surface stability. The results are compared to the STC performance guidelines of 6 mm to 11 mm for a Community Field and 6 mm to 10 mm for Stadium Field. Vertical Deformation typically will reduce over time as a field receives use.

[0018] Energy Restitution (%)(STC Advanced Artificial Athlete Protocol test) Measures the energy returned as a percentage of the energy of applied. This can be thought of as the springiness of the surface. This value relates to the feel underfoot as well as the speed of play. Although this measurement is not a part of the official standard, it is a useful measure. The recommended range is 20% to 50%.

[0019] ASTM F355A Gmax/HIC Impact Attenuation (Flat Faced Drop Missile) (G's (Units of Gravity))The ASTM F355A Impact Hardness is the official device/method for assessing the hardness of synthetic turf athletic fields. It is used to gauge impact attenuation based on a predetermined head/body impact. This is a 20 Ib missile with a tri-axial accelerometer dropped from a height of 24 in. The STC recommends that the Gmax values be less than 165.

[0020] EN 1177HIC Impact Attenuation (Hemispherical Drop Missile) (Critical Fall Height (m))The EN 1177Impact attenuating play surfacing determination of critical fall height method is similar to the method commonly used for assessing playground surfacing in the United States. Internationally it is the primary method for both synthetic turf and playground surfacing. This device calculates the Head Injury Criteria (HIC). This is used to gauge the probability of head injury potential resulting from a surface impact. This device is a hemispherical 10 lb missile with a tri-axial accelerometer. The hemisphere is dropped from (4) different heights to determine the height at which the HIC would be 1000. This height is referred to as the critical fall height. It is recommended that the critical fall height values be greater than 1.3 meters.

[0021] Rotational ResistanceEN15301 (Newton Meters (n))Rotational Resistance measures the interaction between the cleat sole and the surface relating to the ability of a player to change direction. Higher values can relate to a surface that resists the rotation of a foot when a player is changing direction and increase the potential for lower extremity injury. STC guidelines recommend the results being 30 n to 45 n.

[0022] Vertical Ball ReboundEN 12235 (Meters (m))Measures how high the ball bounces when falling vertically onto a synthetic turf field. A ball is released from 2 m and the height of its rebound from the surface is calculated. The ball is first calibrated on a level concrete surface to 1.35 m. STC recommends from 0.60 to 0.85 m.

[0023] Following Tables I-III provide the test results, conducted indoors, for each of the compared particulates in the respective artificial turf system:

TABLE-US-00001 TABLE I 20s/ 70/30 70/30 TEST UNITS 50TPE_PriorArt Pre-Wear Post-Wear Force Reduction % 66 59 57 Vertical Def mm 9 8 7.9 Energy Restit % 23 26 26 355A Flat Gmax G 108 133 137 355A Flat HIC 269 374 401 Critical Fall Height m 1.2 1 1 Rotational n 30 32 30 Resistance Ball Rebound m 0.9 0.92 0.70

TABLE-US-00002 TABLE II Relative 70/30 Pre- Absolute Diff./ % Difference TEST UNITS 20 s/50TPE_PriorArt Wear Difference Comment (Decimal) Force Reduction % 66 59 Increase Decrease 0.106 7% over 10% Vertical Def mm 9 8 Decrease Decrease 0.111 1 mm over 10% Energy Restit % 23 26 Increase Increase 0.130 3% about 13% 355A Flat G 108 133 Increase Increase 0.231 Gmax 25 about 23% 355A Flat HIC 269 374 Increase Increase 0.390 105 about 40% Critical Fall m 1.2 1 Decrease Decrease 0.167 Height 0.2 m over 15% Rotational n 30 32 Increase Increase 0.067 Resistance 2 n over 5% Ball Rebound m 0.9 0.92 Increase Increase 0.022 0.02 m about 2%

TABLE-US-00003 TABLE III Relative 70/30 Pre- 70/30 Post- Absolute Diff./ % Difference TEST UNITS Wear Wear Difference Comment (Decimal) Force Reduction % 59 57 Decrease Decrease 0.15254 2% of 15% Vertical Def mm 8 7.9 Decrease Decrease 0.13750 0.1 mm over 10% Energy Restit % 26 26 None None 0.000 355A Flat G 133 137 Increase Increase 0.03008 Gmax 4 3% 355AFlatHIC 374 401 Increase Increase 0.07219 27 7% Critical Fall m 1 1 None None 0.000 Height Rotational n 32 30 Decrease Decrease 0.06250 Resistance 2 n about 6% Ball Rebound m 0.92 0.79 Decrease Decrease 0.14130 0.13 m about 14%

[0024] The results of tests set forth in Tables I-III indicate that embodiments of the invention using PVC infill pellets and granules having a variety of multiple sizes and irregular shapes, such as non-symmetrical shapes, that are dispersed as infill in artificial turf installations impart improved performance characteristics to the artificial turf over convention artificial turf installations.

[0025] Various embodiments of the invention have been described. It will, however, be evident that various modifications and changes may be made thereto, and additional embodiments may be implemented, without departing from the broader scope of the exemplary embodiments as set forth in the claims. This specification is to be regarded in an illustrative rather than a restrictive sense.